Let DM work without a GPU.

dm/DMTestTask.cpp

 #include "DMTestTask.h"
 #include "DMUtil.h"
 #include "SkCommandLineFlags.h"
 
 DEFINE_bool2(pathOpsExtended,     x, false, "Run extended pathOps tests.");
 DEFINE_bool2(pathOpsSingleThread, z, false, "Disallow pathOps tests from using threads.");
 DEFINE_bool2(pathOpsVerbose,      V, false, "Tell pathOps tests to be verbose.");
 
 namespace DM {
 
@@ skipping 32 matching lines @@
 
 void GpuTestTask::draw(GrContextFactory* grFactory) {
     fTest->setGrContextFactory(grFactory);
     fTest->setReporter(&fTestReporter);
     fTest->run();
     if (!fTest->passed()) {
         this->fail(fTestReporter.failure());
     }
 }
 
+bool GpuTestTask::shouldSkip() const {
+    return kGPUDisabled;
+}
+
 }  // namespace DM